Exploratory data analysis for fatty acid composition in pig meat

Fat content and composition are determinant factors affecting pork production and meat quality (Wood et al., 2003). Fat composition is commonly presented as the percentage of each individual fatty acid relative to total fatty acids and then some pork quality traits are described in terms of some fatty acid percentages (see for example the review by Wood et al., 2008). Despite being compositional in nature, to our knowledge there is no reference in the literature where specific compositional data analysis methods had been applied to analyze fatty acid composition. A first objective of this contribution is to analyze fatty acid composition as compositional data. In meat quality research, it is common to analyze the effect of some influential factors (such as diet, genotype, gender, live weight or age, among others) on fat content and composition, usually the subcutaneous (SF) or the intramuscular (IMF) fats. In these studies, the aim is mostly to estimate and then test the differences among treatments for fatty acid percentages. The pattern of fatty acid deposition may differ among tissue (for instance, SF or IMF) or muscle (Kloareg et al., 2007; Duran-Montgé et al., 2008), and even between localization within a specific tissue. A second objective of this manuscript is to better know the differences between fatty acid deposition pattern between tissues, localization within a tissue, and muscles. Thus, the purpose of the present study is, first, to describe a data set of fatty acid composition collected specifically for doing research on IMF content and composition and assess the main differences among IMF of three muscles and SF using compositional data methods, and, second, to apply, as a case study, specific compositional data methods to discriminate between samples of IMF and SF by fatty acid composition and compare the results with the obtained when using the traditional approach

A compositional genetic analysis of oleic acid content in pig meat

Intramuscular fat (IMF) content and composition, particularly the oleic fatty acid content (OL), are major quality characteristics of pork fresh and dry-cured products. They are known to be related to nutritional, manufacturing and organoleptic properties, as well as to human health. It is known that IMF content is under genetic control but little evidence is available for IMF composition, namely OL. There are very few estimates in the literature regarding genetic parameters for OL (Suzuki et al., 2006) and, besides, most of them are based on small data sets from experiments designed for other purposes (Ntawubizi et al., 2010; Sellier et al., 2010). However, genetic parameters associated to IMF and OL (i.e. heritability and genetic correlations with other relevant traits) are needed for developing selection criteria and optimum breeding strategies and programmes. IMF content is usually expressed in percent of dry or wet matter and OL in percent of total fatty acids in IMF. However, all research done in this field was not aware of the compositional nature of these data (Aitchison, 1986). The purpose of the present contribution is to compare results from standard linear with compositional data analyses for IMF and OL. Analyses were compared in terms of genetic parameter estimates, selection efficiency, and predictive capacity

Acoustic properties of agroforestry waste orange pruning fibers reinforced polypropylene composites as an alternative to laminated gypsum boards

The present paper investigates the acoustic properties of natural fiber reinforced composites. Fibers from orange tree pruning were obtained and subject to different treatments in order to obtain mechanical, thermomechanical and chemi-thermomechanical pulps. These pulps were used as reinforcement for a polypropylene matrix. The obtained composite materials were submitted to acoustical tests in an impedance tubes device. The transmission losses obtained against the fiber content were obtained and discussed. Latter it was researched the influence of the fiber treatments on the soundproof characteristics. A numerical method was used to preview the acoustic insulation of the materials against the sound frequency. Finally the results were compared with that of the most usual lightweight soundproof solutions. (C) 2014 Elsevier Ltd. All rights reserved.Reixach, R.; Rey Tormos, RMD.; Alba Fernández, J.; Arbat, G.; Espinach, FX.; Mutjé, P. (2015). Acoustic properties of agroforestry waste orange pruning fibers reinforced polypropylene composites as an alternative to laminated gypsum boards. Construction and Building Materials. 77:124-129. doi:10.1016/j.conbuildmat.2014.12.041S1241297

Transthyretin Aggregation Pathway toward the Formation of Distinct Cytotoxic Oligomers

Characterization of small oligomers formed at an early stage of amyloid formation is critical to understanding molecular mechanism of pathogenic aggregation process. Here we identifed and characterized cytotoxic oligomeric intermediates populated during transthyretin (TTR) aggregation process. Under the amyloid-forming conditions, TTR initially forms a dimer through interactions between outer strands. The dimers are then associated to form a hexamer with a spherical shape, which serves as a building block to self-assemble into cytotoxic oligomers. Notably, wild-type (WT) TTR tends to form linear oligomers, while aTTR variant(G53A) prefers forming annular oligomers with pore-like structures. Structural analyses of the amyloidogenic intermediates using circular dichroism (CD) and solid-state NMR revealthatthe dimer and oligomers have a signifcant degree of native-like β-sheet structures (35–38%), but with more disordered regions (~60%)than those of nativeTTR.TheTTR variant oligomers are also less structured than WT oligomers. The partially folded nature of the oligomeric intermediates might be a common structural property of cytotoxic oligomers.The higher fexibility of the dimer and oligomers may also compensate for the entropic loss due to the oligomerization of the monomers

Amitriptyline-Mediated Cognitive Enhancement in Aged 3×Tg Alzheimer's Disease Mice Is Associated with Neurogenesis and Neurotrophic Activity

Approximately 35 million people worldwide suffer from Alzheimer's disease (AD). Existing therapeutics, while moderately effective, are currently unable to stem the widespread rise in AD prevalence. AD is associated with an increase in amyloid beta (Aβ) oligomers and hyperphosphorylated tau, along with cognitive impairment and neurodegeneration. Several antidepressants have shown promise in improving cognition and alleviating oxidative stress in AD but have failed as long-term therapeutics. In this study, amitriptyline, an FDA-approved tricyclic antidepressant, was administered orally to aged and cognitively impaired transgenic AD mice (3×TgAD). After amitriptyline treatment, cognitive behavior testing demonstrated that there was a significant improvement in both long- and short-term memory retention. Amitriptyline treatment also caused a significant potentiation of non-toxic Aβ monomer with a concomitant decrease in cytotoxic dimer Aβ load, compared to vehicle-treated 3×TgAD controls. In addition, amitriptyline administration caused a significant increase in dentate gyrus neurogenesis as well as increases in expression of neurosynaptic marker proteins. Amitriptyline treatment resulted in increases in hippocampal brain-derived neurotrophic factor protein as well as increased tyrosine phosphorylation of its cognate receptor (TrkB). These results indicate that amitriptyline has significant beneficial actions in aged and damaged AD brains and that it shows promise as a tolerable novel therapeutic for the treatment of AD

Cholera Toxin B Subunits Assemble into Pentamers - Proposition of a Fly-Casting Mechanism

The cholera toxin B pentamer (CtxB5), which belongs to the AB5 toxin family, is used as a model study for protein assembly. The effect of the pH on the reassembly of the toxin was investigated using immunochemical, electrophoretic and spectroscopic methods. Three pH-dependent steps were identified during the toxin reassembly: (i) acquisition of a fully assembly-competent fold by the CtxB monomer, (ii) association of CtxB monomer into oligomers, (iii) acquisition of the native fold by the CtxB pentamer. The results show that CtxB5 and the related heat labile enterotoxin LTB5 have distinct mechanisms of assembly despite sharing high sequence identity (84%) and almost identical atomic structures. The difference can be pinpointed to four histidines which are spread along the protein sequence and may act together. Thus, most of the toxin B amino acids appear negligible for the assembly, raising the possibility that assembly is driven by a small network of amino acids instead of involving all of them

Amyloid Oligomer Conformation in a Group of Natively Folded Proteins

Recent in vitro and in vivo studies suggest that destabilized proteins with defective folding induce aggregation and toxicity in protein-misfolding diseases. One such unstable protein state is called amyloid oligomer, a precursor of fully aggregated forms of amyloid. Detection of various amyloid oligomers with A11, an anti-amyloid oligomer conformation-specific antibody, revealed that the amyloid oligomer represents a generic conformation and suggested that toxic β-aggregation processes possess a common mechanism. By using A11 antibody as a probe in combination with mass spectrometric analysis, we identified GroEL in bacterial lysates as a protein that may potentially have an amyloid oligomer conformation. Surprisingly, A11 reacted not only with purified GroEL but also with several purified heat shock proteins, including human Hsp27, 40, 70, 90; yeast Hsp104; and bovine Hsc70. The native folds of A11-reactive proteins in purified samples were characterized by their anti-β-aggregation activity in terms of both functionality and in contrast to the β-aggregation promoting activity of misfolded pathogenic amyloid oligomers. The conformation-dependent binding of A11 with natively folded Hsp27 was supported by the concurrent loss of A11 reactivity and anti-β-aggregation activity of heat-treated Hsp27 samples. Moreover, we observed consistent anti-β-aggregation activity not only by chaperones containing an amyloid oligomer conformation but also by several A11-immunoreactive non-chaperone proteins. From these results, we suggest that the amyloid oligomer conformation is present in a group of natively folded proteins. The inhibitory effects of A11 antibody on both GroEL/ES-assisted luciferase refolding and Hsp70-mediated decelerated nucleation of Aβ aggregation suggested that the A11-binding sites on these chaperones might be functionally important. Finally, we employed a computational approach to uncover possible A11-binding sites on these targets. Since the β-sheet edge was a common structural motif having the most similar physicochemical properties in the A11-reactive proteins we analyzed, we propose that the β-sheet edge in some natively folded amyloid oligomers is designed positively to prevent β aggregation